PSR PSR-1: Basic Coding Standard PSR-3: Logger Interface PSR-4: Autoloader PSR-6: Caching Interface PSR-7: HTTP message interfaces PSR-11: Container interface PSR-12: Extended Coding Style PSR-13: Link definition interfaces PSR-14: Event Dispatcher PSR-15: HTTP Server Request Handlers PSR-16: Common Interface for Caching Libraries PSR-17: HTTP Factories PSR-18: HTTP Client PSR-20: Clock